JPS63151427A - Orientation method for polyether image film - Google Patents

Abstract

PURPOSE:To prepare good orienting properties at a low temperature by immersing a polyether imide non-oriented film into a mixed solvent of halogenated carbon hydride and aliphatic alcohol and orienting thus prepared swelled film in a mixed solvent of halogenated carbon hydride and aliphatic alcohol. CONSTITUTION:Polyether imide is synthesized by replacing, for polymerization, nitro radical of bisimide, which is nitro-substituted by reacting nitrophthalic acid achydride with diamine, with dianion of bisphenols, and it is shown by formula (1). A swelling agent or heat medium for orientation for swelling and orienting polyether imide film is a mixed solvent of a good solvent to solve polymer and a poor solvent not to solve polymer but compatible with the good solvent. By using a mixed solvent of halogenated carbon hydride as good solvent and a aliphatic alcohol as poor solvent, good swelling and orienting properties to the polyether imide film is developed and an oriented film of desired characteristics can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for sufficiently stretching a polyetherimide film or sheet having excellent heat resistance, electrical insulation, etc. without thermally decomposing it.

[Background Art] In the fields of electrical and electronic materials, there is an increasing need to develop electrical and electronic devices that are small, lightweight, and have high performance. In order to satisfy these demands, there is a need for something that can exhibit sufficient heat resistance, electrical insulation, etc. even if it is miniaturized, and improvements in the material itself are also increasing. A typical example of improved polymers that have been proposed so far is fully aromatic polyimide (aromatic diamine), which has excellent not only heat resistance and electrical insulation properties but also mechanical properties.
Examples include polycondensates of diaminodiphenyl ether) and pyromellitic anhydride [e.g. poly(4°47-oxyphenylenepyromellitimide)], which have short-term heat resistance of 400°C or higher and long-term heat resistance of 260°C or higher. There were also high expectations for the performance.

However, this fully aromatic polyimide has poor mechanical properties as described above, and due to its rigid molecular structure, it has poor melt flowability and cannot be extruded into films or sheets. One of the disadvantages is that it is problematic and expensive.

Therefore, research has been carried out on new types of polyimides that can achieve both good moldability and low cost while maintaining heat resistance, and polyetherimide has been proposed as one of them.

That is, polyetherimide is a polymer material that has aromatic imide rings and ether bonds in its molecular chain, and has excellent thermal, electrical, and mechanical properties based on aromatic polyimide, and also has It is a non-grade thermoplastic polymer with flexibility imparted to the polymer chain and good melting properties. Polyetherimide films or sheets have excellent heat resistance and electrical insulation properties, so they can be used as electrical insulation films such as insulating the slots of motors, base films for flexible printed wiring boards, films for capacitors, and printed circuit boards made by injection molding. It is also used as an information recording material for magnetic disks, optical disks, etc. due to its excellent heat resistance, toughness, and dimensional accuracy.

[Problems to be Solved by the Invention] Polyetherimide films can be produced by melt extrusion of polyetherimide resin or casting of polyetherimide resin solution, but
In order to further improve the strength, impact strength, etc. of IIW, it is necessary to further stretch it. However, since polyetherimide has a high secondary transition point, there is a problem in that good stretchability cannot be obtained. Stretching of thermoplastic polymer films is generally carried out by a dry heat method in a temperature region slightly above the second-order transition point of the polymer, that is, in the transition region from a rubber state to a glass state. It has a rigid main chain, a high secondary transition point, and high strength and high modulus. That is, the thermal movement of the molecular chains is inhibited and sufficient stretchability cannot be obtained. Furthermore, since the secondary transition point is high, the stretching temperature becomes high, which not only tends to cause thermal decomposition during stretching, but also requires high temperatures, making it uneconomical in terms of thermal energy.

The present invention has been made in view of these circumstances, and it is an object of the present invention to provide a method for stretching a polyetherimide film that can be stretched at a lower temperature and can obtain good stretchability. It is something.

[Means for Solving the Problems] The method of the present invention which achieves the above object is to immerse an unstretched film of polyetherimide in a mixed solvent of a halogenated hydrocarbon and an aliphatic alcohol, and to obtain a swollen film. The gist of this method is that it is stretched in a mixed solvent of a halogenated hydrocarbon and an aliphatic alcohol.

[Function] When stretching a polyetherimide film or sheet, the present invention immerses the film or sheet in a swelling agent in advance to swell it, and then heat-stretches it in a stretching heating medium, thereby stretching the polyetherimide film or sheet beyond the secondary transition point. It is designed so that good stretchability can be obtained even when stretched at a low temperature. That is, the film or sheet is swollen and plasticized by immersion in a swelling agent prior to hot stretching, and the swelling and plasticizing effects work synergistically to cause the secondary transition point of the film or sheet to appear to rise. do. By subjecting the film or sheet immersed in a swelling agent to hot stretching, which has a lower stretching temperature than dry heat stretching, the stretching temperature can be further reduced;
This has succeeded in ensuring good stretchability even when stretching at a temperature lower than the secondary transition point. However, when applying the above-mentioned swelling wet heat stretching technique to stretching a polyetherimide film or sheet, it is necessary to appropriately select a swelling agent and a stretching heating medium that fully consider the properties of the polymer. In all cases, a mixed solvent of halogenated hydrocarbon and aliphatic alcohol was used as the drawing heating medium. The above mixed solvent as the swelling agent and the above mixed solvent as the drawing heating medium may be the same or different. By employing the stretching method described above, it is possible to reduce the thermal energy consumption compared to the conventional method, and it is also possible to prevent thermal decomposition of the polymer by lowering the stretching temperature.

The swelling agent may be removed from the stretched film after swelling and stretching by methods such as air drying and reduced pressure drying.

The polyetherimide mentioned here is synthesized by substituting and polymerizing the nitro group of nitro-substituted bisimide with the dianion of bisphenols through the reaction of nitrophthalic anhydride and diamine, and has the following chemical structural formula (1). It may be a composition consisting only of the indicated composition, or a composite composition containing it as a main component.

Hydrogen residue: aliphatic hydrocarbon residue such as (CH2)8;
Examples of Ar include aromatic ether residues such as φΣ. Examples of Ar include diphenyl sulfide residues such as bisphenol A residue; hydroquinone residue; and resorcinol residue. Among the polyetherimides used in this, the most typical one is one having the following chemical structural formula (2).

Next, the components to be blended with the polyetherimide represented by the chemical structural formula (1) to form a composite composition include polypropylene, polyamide, polyester, polyacrylate, polycarbonate, polymethyl methacrylate,
polystyrene, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyetherketone,
Thermoplastic polymers such as polyetheretherketone are exemplified, and one or more combinations of other components selected from lubricants, ultraviolet absorbers, antistatic agents, heat stabilizers, etc. may be used.

The swelling agent or stretching heating medium used for swelling and stretching the polyetherimide film is a mixed solvent of a good solvent that dissolves the polymer and a poor solvent that does not dissolve the polymer but is compatible with the good solvent. As the above-mentioned good solvent, halogenated hydrocarbons such as methylene chloride, ethylene chloride, trichloroethylene, and chloroform are used.
On the other hand, aliphatic alcohols such as methyl alcohol, ethyl alcohol, and n-butyl alcohol are used as the poor solvent. The reason why such a combination of mixed solvents is used as a swelling agent or stretching solvent in the present invention is that if a solvent consisting only of good solvents is used as a swelling agent, the polyetherimide film immersed in it will dissolve and remain in a swollen state. This is because it is not possible. If a solvent consisting only of good solvents is used as a stretching heating medium, the polyetherimide film will dissolve during stretching, resulting in breakage of the film. On the other hand, when a solvent consisting only of a poor solvent is used as a swelling agent, the solvent does not sufficiently penetrate into the film, making it impossible to swell the film. Furthermore, when a solvent consisting only of a poor solvent is used as a heating medium for stretching, there arises the disadvantage that a sufficient stretching ratio cannot be obtained. On the other hand, when a mixed solvent consisting of a halogenated hydrocarbon as a good solvent and an aliphatic alcohol as a poor solvent is used as a swelling agent and stretching heating medium, good swelling and stretching properties are achieved for polyetherimide films. Stretched films with desired properties can be obtained. If a good solvent other than a halogenated hydrocarbon and/or a poor solvent other than an aliphatic alcohol is used, various disadvantages may occur as shown in the Examples and Comparative Examples below, and satisfactory stretchability etc. may not be achieved. I can't.

Further, in the present invention, there is no particular restriction on the blending ratio of halogenated hydrocarbon and aliphatic alcohol, but preferably halogenated hydrocarbon: aliphatic alcohol = (30-70) = (70-30). It is hoped that Outside this range, the solvent properties become close to those of a good solvent or a poor solvent, and the drawbacks of each solvent become apparent.

[Example] Example 1 Polyetherimide resin represented by the chemical structural formula (2) (polyetherimide resin ULTEM manufactured by GE)
1000) in methylene chloride to give a polymer concentration of 10
A polyetherimide resin solution of % by weight was prepared, cast into a film, and dried to obtain a film with a thickness of 730 μm. This unstretched film was mixed with 50% by weight of methylene chloride and n-
A swelling agent consisting of 50% by weight of butyl alcohol at 20°C.
Soaked for about 2 hours. Using this swollen film, free width-axis stretching was performed at 20° C. in a medium containing the swelling agent described above. As a result, a high stretchability of 550% was obtained.

Comparative Example 1 The swollen film of Example 1 was stretched normally in air instead of in a swelling agent bath, but the stretchability was poor (the film turned white) and the stretching ratio was limited to 250%, and it was difficult to stretch it further. Then a rupture occurred.

Comparative Example 2 When the unstretched film of Example 1 was subjected to normal stretching in air without swelling, the maximum stretching ratio was 250%.

Comparative Example 3 When the unstretched film of Example 1 was swollen in a solvent containing 100% methylene chloride, the film dissolved and could not be stretched.

Comparative Example 4 The unstretched film of Example 1 was mixed with 10% n-butyl alcohol.
When it was swollen in a 0% solvent, it could not be swelled sufficiently.

Comparative Example 5 When the unstretched film of Example 1 was stretched in a mixed solvent of 50% by weight of halogenated hydrocarbon and 50% by weight of n-butyl alcohol without swelling, the central portion of the film between the chucks was stretched. However, since the chuck part did not try to stretch sufficiently, it broke at the chuck part at the same time as the stretching started.

Example 2 and Comparative Examples 6 to 9 A mixed solvent of 50% by weight of methylene chloride and 50% by weight of a poor solvent was prepared as a swelling agent and a drawing heating medium by changing the type of poor solvent, and swelling and heating were performed in the same manner as in Example 1. When stretching was carried out, the results shown in Table 1 below were obtained.

Table 1 Table 2 Comparative Examples 10 to 13 As shown in Table 2, the types of good solvents were changed and 5 good solvents were used.
When a mixed solvent of 0% by weight and 50% by weight of n-butyl alcohol was prepared and swelling and stretching were carried out in the same manner as in Example 1, the film could not be sufficiently swollen in either case, resulting in satisfactory stretching. I couldn't do it.

[Effects of the Invention] The present invention is configured as described above, and can sufficiently stretch a polyetherimide film at low temperatures, providing a stretched film that has excellent heat resistance, electrical insulation properties, and mechanical properties. I closed it so that I could do it.

Claims (1)

[Claims] It is characterized by immersing an unstretched film of polyetherimide in a mixed solvent of a halogenated hydrocarbon and an aliphatic alcohol, and stretching the obtained swollen film in a mixed solvent of a halogenated hydrocarbon and an aliphatic alcohol. A method for stretching polyetherimide film.